ML17199F667
| ML17199F667 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Dresden |
| Issue date: | 02/28/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17199F665 | List: |
| References | |
| TAC-41245, NUDOCS 8603110163 | |
| Download: ML17199F667 (2) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATING TO RADIOLOGICAL CONSEQUENCES OF A LOCA WHILE PURriING CONTAINMENT COMMONWEALTH EDISON COMPANY DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 DOCKET NOS. 50-237/249
1.0 INTRODUCTION
The staff has reviewed the radiological consequences of a hypothetical LOCA while purging the containment at power for Dresden, Unit Nos. 2 and
- 3.
This evaluation was conducted under Multi-Plant Issue B-24 and in accordance with the guidance of Branch Technical Position CSB 6-4, Standard Review Plan Sections 6.2.4 and 15.6.5 and Regulatory Guide 1.3.
2.0 EVALUATION Our evaluation is based on the release of 660 pounds mass (lbm) of steam prior to the post-LOCA closure of the purge valves at the maximum Technical Specification primary coolant concentration of 20 uCi/gm, dose equivalent I-131. It was assumed that the containment isol~tion would be achieved before the onset of fuel failure resultinQ from the a~cident. A 0.5% directionally dependent X/O value was used.
A list of applicable assumptions is given in 1able 1.
The staff estimates that the steam released through the purge line*
would result in an incremental dose of 0.76 Rem to the thyroid at the Exclusion Area Boundary (EAB) and 0.1 Rem to the thyroid at the Low Population Zone Boundary (LPZ).
These doses when ~dded to the staff Systematic Evaluation Program (SEP) Review of Topic XV-19 LOCA doses bf 30 Rem to the thyroid at the EAR and 230 Rem to the thyroid at the LPZ (See Table 2) meet the applicable guidelines of 10 CFR Part 100.
3.0 CONCLUSION
- We conclude, therefore, that the radiological consequences of a LOCA during purging at Dresden Unit Nos. 2 and 3 meet the applicable guide-lines of 10 CFR Part 100, and are therefore acceptable.
Principal Contributors:
K. Dempsey Dated: February 28, 1986
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.Dr~sden, Unit Nos. 2/3 TABLE 1 ASSUMPTIONS USED TO EVALUATE THE CONTAINMENT PURGE CONTRIBUTION TO THE LOCA DOSE
(
)
3
-4 X/Q value 0-2 hour, EAB, ground level rel!ase, sec/m 2.6 x 10_6 (0-8 hour, LPZ, elevated), *sec/m
- 1.3 x 10 Purge valve closure time, sec 10 A~ount of steam released through the purge valves prior to 660 post-LOCA closure, lbm Maximum technical specification primary coolant limit, 20 dose-equivalent I-131, µCi/gm TABLE 2 RADIOLOGICAL CONSEQUENCES Containment purge contribution SEP lOCA dose Effective LOCA dose NOTES:
THYROID DOSE EAB, 0-2 HOUR LPZ, 30 DAYS 0.76 Rem
. 30.0 Rem 31 Rem 0.1 Rem 230.0 Rem 230 Rem
- 1. The X/Q value was taken from the NRC Plant Data File, updated 5/12/83.
- 2. The whole body doses are not listed because they would be negligible when compared to the guideline values. The LPZ dose would be less than the EAB dose.